Inhibition of Human Prostate and Bladder Smooth Muscle Contraction, Vasoconstriction of Porcine Renal and Coronary Arteries, and Growth-Related Functions of Prostate Stromal Cells by Presumed Small Molecule Gαq/11 Inhibitor, YM-254890

Voiding symptom severity varies independently from non-adrenergic prostate smooth muscle contractions in patients undergoing surgery for benign prostatic hyperplasia

Background

Resistance of voiding symptoms to α1-blockers in benign prostatic hyperplasia (BPH) has been provisionally explained by non-adrenergic prostate smooth muscle contraction. Here, we examined relationships between contractions and voiding symptoms in prostate tissues from laser-enucleation.

Methods

Tissues were obtained from holmium and thulium laser enucleation. Contractions were induced by endothelin-1, U46619, noradrenaline and electric field stimulation (EFS). Emax values were analyzed for correlation with international prostate symptom score (IPSS), and compared to tissues from patients without surgery for BPH.

Results

Noradrenaline- and EFS-induced contractions were higher with severe (IPSS 20-35) than moderate symptoms (IPSS 8-19) (Emax noradrenaline 66% vs 113% of KCl-induced contractions; EFS 33% vs 66%). Endothelin-1- and U46619-induced contractions were already maximum with moderate symptoms (endothelin-1 117% moderate, 135% severe; U46619 23%, 27%). Within 8-21 points, IPSS increased with Emax values for noradrenaline and EFS (r = 0.545, r = 0.448), but not with endothelin-1- or U46619-induced contractions. Endothelin-1-induced contractions were similar to noradrenaline-induced contractions (Emax endothelin-1 126% of KCl, noradrenaline 96%), and exceeded EFS- (52%) and U46619-induced contractions (25%). Emax values for endothelin-1 were similar between laser-enucleated patients and patients without surgery for BPH (127%), while Emax values for U46619 were higher in tissues from patients without surgery for BPH (59%) compared to laser-enucleated tissues.

Conclusion

Symptom severity increases with α1-adrenergic, but not with non-adrenergic contractions in patients undergoing surgery for BPH. Endothelin-1-induced contractions are similar to noradrenaline-induced contractions. Conditions necessitating BPH surgery may not necessarily depend on α1-adrenergic tone, but may involve non-adrenergic contractions or factors beyond contraction.

Silencing of Rac1 and Arf6 reduces time-dependent and carbachol-induced contractions, proliferation, survival and growth in human bladder smooth muscle cells

PURPOSE

Storage symptoms in overactive bladder are explained by detrusor contractions and bladder wall thickening. Arf6 and Rac1 are monomeric GTPases with newly emerging roles in smooth muscle contraction and proliferation. Here, we investigated human bladder smooth muscle cells (hBSMC) functions after silencing of Arf6 or Rac1.

METHODS

hBSMC were transfected with Arf6- or Rac1-specific or scrambled siRNA (controls), and characterized using collagen contraction assays, for proliferation (EdU, Ki67), viability, growth in colony formation assays and actin organization.

RESULTS

Arf6 and Rac1 silencing was confirmed by RT-PCR. Time-dependent contractions (0.5-6 h after assay initiation) were reduced in Arf6- and Rac1-silenced cells (36% Arf6, 28% Rac1, after 6 h), compared to scramble-transfected cells. Carbachol (3 µM) increased the time-dependent contractions, which were reduced by silencing of Arf6 (40-62%, 0.5-6 h) or Rac1 (30-59% at 0.5-6 h). With U46619 or endothelin-1, time-dependent contractions were similar to contractions without agonists, but again reduced in Arf6- and Rac1-silenced cells. Compared to scramble-transfected cells, silencing reduced the proliferation rate (Arf6 52%, Rac1 33%), Ki67 mRNA expression (89%, 91%), colony formation (63%, 66%), viability (Arf6 up to 84%, Rac1 up to 85%), and actin polymerization (30%, 31%).

CONCLUSIONS

Arf6 and Rac1 promote time-dependent and carbachol-induced contractions of hBSMC, which may be mediated by actin polymerization. Simultaneously, Arf6 and Rac1 promote proliferation, growth and survival in hBSMC. Arf6 and Rac1 may be potentially involved in detrusor overactivity, bladder wall thickening and medical treatment of overactive bladder.

Smooth muscle contractility of laser-enucleated prostate tissues and impacts of preoperative α1-blocker treatment in patients with and without catheterization

Prostate smooth muscle contraction is central in treatment of voiding symptoms in benign prostatic hyperplasia (BPH). Tissues from transurethral resection of the prostate (TURP) and radical prostatectomy (RP) for prostate cancer are widely used to study contractions. However, findings are limited by traumatization in TURP, and uncertain relationship to BPH in RP tissues. This study aims to examine contractions of laser-enucleated tissues. Tissues from holmium/thulium laser enucleation (HoLEP/ThuLEP) and TURP were contracted by KCl, noradrenaline and electric field stimulation (EFS) in an organ bath. Contractions were compared to RP tissues in previous studies. KCl-induced contractions averaged 2.5 mN, 0.7 mN and 3.3 mN in tissues from HoLEP/ThuLEP, TURP and RP, with non-responsive tissues included (2.4% HoLEP/ThuLEP, 37% TURP). Maximum EFS-induced contractions (Emax) averaged 47% of KCl in HoLEP/ThuLEP tissues, 27% in TURP tissues, and 68-235% in 21 previous studies with RP tissues. Emax values for noradrenaline averaged 99.7% in HoLEP/ThuLEP tissues, 56% in TURP tissues, and ranged from 92 to 260% in RP tissues. Preoperative α1-blocker treatment reduced EFS- and noradrenaline-induced contractions, and increased EC50 values for noradrenaline in laser-enucleated, catheterized patients, but not in patients without catheterization. Also, the ex vivo application of α1-blockers increased the EC50 values for noradrenaline and reduced Emax for EFS. Laser-enucleated tissues allow investigation of prostate smooth muscle contraction in medication-refractory voiding symptoms. Different impacts of preoperative α1-blocker treatment on ex vivo contractility in tissues from patients with and without catheterization point to clinically relevant heterogeneity of patients undergoing surgery for BPH.

Immunomodulatory imide drugs inhibit human detrusor smooth muscle contraction and growth of human detrusor smooth muscle cells, and exhibit vaso-regulatory functions

BACKGROUND

The immunomodulatory imide drugs (IMiDs) thalidomide, lenalidomide and pomalidomide may exhibit therapeutic efficacy in the prostate. In lower urinary tract symptoms (LUTS), voiding and storage disorders may arise from benign prostate hyperplasia, or overactive bladder. While current therapeutic options target smooth muscle contraction or cell proliferation, side effects are mostly cardiovascular. Therefore, we investigated effects of IMiDs on human detrusor and porcine artery smooth muscle contraction, and growth-related functions in detrusor smooth muscle cells (HBdSMC).

METHODS

Cell viability was assessed by CCK8, and apoptosis and cell death by flow cytometry in cultured HBdSMC. Contractions of human detrusor tissues and porcine interlobar and coronary arteries were induced by contractile agonists, or electric field stimulation (EFS) in the presence or absence of an IMID using an organ bath. Proliferation was assessed by EdU assay and colony formation, cytoskeletal organization by phalloidin staining, RESULTS: Depending on tissue type, IMiDs inhibited cholinergic contractions with varying degree, up to 50 %, while non-cholinergic contractions were inhibited up to 80 % and 60 % for U46619 and endothelin-1, respectively, and EFS-induced contractions up to 75 %. IMiDs reduced viable HBdSM cells in a time-dependent manner. Correspondingly, proliferation was reduced, without showing pro-apoptotic effects. In parallel, IMiDs induced cytoskeletal disorganization.

CONCLUSIONS

IMiDs exhibit regulatory functions in various smooth muscle-rich tissues, and of cell proliferation in the lower urinary tract. This points to a novel drug class effect for IMiDs, in which the molecular mechanisms of action of IMiDs merit further consideration for the application in LUTS.

Overview of current pharmacotherapeutic options in benign prostatic hyperplasia

INTRODUCTION

Benign prostatic hyperplasia (BPH) represents the histological entity of prostate cell proliferation, which inflicts a gradually increasing obstruction of the bladder outlet and is accompanied by a progressing manifestation of lower urinary tract symptoms (LUTS). BPH management algorithm includes conservative measures, pharmaceutical agents, and surgical procedures.

AREAS COVERED

A comprehensive literature review was performed using PubMed, Scopus, and Google Scholar databases to identify publications written in English, analyzing BPH pharmaceutical treatment. The search was conducted from January 2000 to January 2023. Six main drug classes can be administered, either as monotherapy or in combination. Furthermore, the authors provide current direction of research on future medications, which focuses on a more etiological interference to the BPH pathophysiological mechanism.

EXPERT OPINION

The available medications represent an effective first-line step of BPH/LUTS therapy. Currently, the administration of BPH medications is tailored to patient/disease characteristics and entails long-time adherence to therapy. The emergence of new surgical modalities, which combine significantly lower morbidity compared to standard procedures and more durable effects than the available medications, seems to challenge the current treatment algorithm. More direct comparisons and the increasing experience with these surgical modalities will delineate the switch points between various therapy levels along the BPH management sequence.

Treating LUTS in Men with Benign Prostatic Obstruction: A Review Article

Benign prostatic obstruction (BPO) is a prevalent condition that affects men, primarily toward their old age. The condition is often accompanied by lower urinary tract symptoms (LUTS), which can significantly impair a patient's quality of life and lead to other medical complications. Accurate diagnosis of BPO is essential for effective management of complications secondary to BPO, and treatment plans should be tailored patients, and occasionally according to surgeon experience. As such, this literature review aims to analyze the current available data on male LUTS secondary to BPO by providing a comprehensive overview of relevant studies, as well as the surgical and medical management guidelines from the Canadian Urological Association (CUA), American Urological Association (AUA), and European Association of Urology (EAU). By synthesizing the existing literature, this review purports to summarize the current body of knowledge surrounding BPO and male LUTS, and support healthcare providers in making informed decisions about the management of male LUTS secondary to BPO, ultimately improving patient outcomes and quality of life.

Current and Emerging Pharmacological Targets and Treatments of Urinary Incontinence and Related Disorders

Overactive bladder syndrome with and without urinary incontinence and related conditions, signs, and disorders such as detrusor overactivity, neurogenic lower urinary tract dysfunction, underactive bladder, stress urinary incontinence, and nocturia are common in the general population and have a major impact on the quality of life of the affected patients and their partners. Based on the deliberations of the subcommittee on pharmacological treatments of the 7th International Consultation on Incontinence, we present a comprehensive review of established drug targets in the treatment of overactive bladder syndrome and the aforementioned related conditions and the approved drugs used in its treatment. Investigational drug targets and compounds are also reviewed. We conclude that, despite a range of available medical treatment options, a considerable medical need continues to exist. This is largely because the existing treatments are symptomatic and have limited efficacy and/or tolerability, which leads to poor long-term adherence. SIGNIFICANCE STATEMENT: Urinary incontinence and related disorders are prevalent in the general population. While many treatments have been approved, few patients stay on long-term treatment despite none of them being curative. This paper provides a comprehensive discussion of existing and emerging treatment options for various types of incontinence and related disorders.

A simple and accurate method to quantify real-time contraction of vascular smooth muscle cell in vitro

Vascular smooth muscle cells (VSMCs) constitute the medial layer of the blood vessel wall. Their contractile state regulates blood flow in physiological and pathological conditions. Current methods for assessing the contractility of VSMCs are not amenable to the high-throughput screening of pharmaceutical compounds. This study aimed to develop a method to address this shortcoming in the field. Real-time contraction was visualized in living VSMCs using the exogenous expression of green fluorescent protein (GFP). Image-Pro Plus software (IPPS) was used to measure various morphological cell indices. In phenylephrine-treated VSMCs, GFP fluorescence imaging was more accurate than brightfield imaging or phalloidin staining in representing VSMC morphology, as measured using IPPS. Among the multiple indices of VSMC shape, area and mean-diameter were more sensitive than length in reflecting the morphological changes in VSMC. We developed a new index, compound length, by combining the mean-diameter and length to differentiate contracted and uncontracted VSMCs. Based on the compound length, we further generated a contraction index to define a single-VSMC contractile status as single-VSMC contraction-index (SVCI). Finally, compound length and SVCI were validated to effectively assess cell contraction in VSMCs challenged with U46619 and KCl. In conclusion, GFP-based indices of compound length and SVCI can accurately quantify the real-time contraction of VSMCs. In future, the new method will be applied to high-throughput drug screening or basic cardiovascular research.

Permixon®, hexane-extracted Serenoa repens, inhibits human prostate and bladder smooth muscle contraction and exerts growth-related functions in human prostate stromal cells

AIMS

Recently, the European Association of Urology recommended hexane-extracted fruit of Serenoa repens (HESr) in their guidelines on management of non-neurogenic male lower urinary tracts symptoms (LUTS). Despite previously lacking recommendations, Permixon® is the most investigated HESr in clinical trials, where it proved effective for male LUTS. In contrast, underlying mechanisms were rarely addressed and are only marginally understood. We therefore investigated effects of Permixon® on human prostate and detrusor smooth muscle contraction and on growth-related functions in prostate stromal cells.

MAIN METHODS

Permixon® capsules were dissolved using n-hexane. Contractions of human prostate and detrusor tissues were induced in organ bath. Proliferation (EdU assay), growth (colony formation), apoptosis and cell death (flow cytometry), viability (CCK-8) and actin organization (phalloidin staining) were studied in cultured human prostate stromal cells (WPMY-1).

KEY FINDINGS

Permixon® inhibited α₁-adrenergic and thromboxane-induced contractions in prostate tissues, and methacholine-and thromboxane-induced contractions in detrusor tissues. Endothelin-1-induced contractions were not inhibited. Neurogenic contractions were inhibited in both tissues in a concentration-dependent manner. In WPMY-1 cells, Permixon® caused concentration-dependent breakdown of actin polymerization, inhibited colony formation, reduced cell viability, and proliferation, without showing cytotoxic or pro-apoptotic effects.

SIGNIFICANCE

Our results provide a novel basis that allows, for the first time, to fully explain the ubiquitous beneficial effects of HESr in clinical trials. HESr may inhibit at least neurogenic, α₁-adrenergic and thromboxane-induced smooth muscle contraction in the prostate and detrusor, and in parallel, prostate stromal cell growth. Together, this may explain symptom improvements by Permixon® in previous clinical trials.